USDOT_BTS_NTAD_Time_Zones eng; USA utf8 dataset Dominic Menegus Bureau of Transportation Statistics (BTS) Geographer 202-306-1587 1200 New Jersey Ave. SE Washington DC 20590 US dominic.menegus@dot.gov pointOfContact 2026-07-15 ISO 19139 Geographic Information - Metadata ISO/TS 19139:2007 solid 9 3857 EPSG Time Zones 2019-07-01 creation 2026-06-28 publication 2023-01-05 revision Bureau of Transportation Statistics (BTS) originator vector The Time Zones dataset was compiled on October 04, 2019 and was updated January 05, 2023 from the Bureau of Transportation Statistics (BTS) and is part of the U.S. Department of Transportation (USDOT)/Bureau of Transportation Statistics (BTS) National Transportation Atlas Database (NTAD). This layer is a digital representation of the geographic boundaries of the nine time zones that cover the United States and its territories (the Atlantic, Eastern, Central, Mountain, Pacific, Alaska, Hawaii–Aleutian, Samoa, and Chamorro time zones). The U.S. Department of Transportation (DOT) oversees the Nation's time zones and the uniform observance of Daylight-Saving Time. The oversight of time zones was assigned to DOT due to the importance of time coordination for transportation related activities. The time zones were established by the Standard Time Act of 1918 and amended by the Uniform Time Act of 1966. Time zones in the U.S. are defined in the U.S. Code, Title 15, Chapter 6, Subchapter IX - Standard Time. The time zone boundaries are defined in the Code of Federal Regulations (CFR), Title 49, Subtitle A, Part 71 - Standard Time Zone Boundaries. Segments used to compile the geospatial layer were derived from the CFR’s time zone descriptions (https://www.ecfr.gov/current/title-49/subtitle-A/part-71). Descriptions consist of segments referencing administrative boundaries, infrastructure, natural features, and geodesic lines. These segments are contained in various data layers in the National Geospatial Data Asset (NGDA) portfolio, the federal government’s authoritative geospatial data repository. Referenced segments were extracted from their NGDA and then merged to form continuous boundaries. In instances where there were multiple scales for a given dataset, the largest scale or most detailed layer was used. The standard time of the Atlantic zone is the Coordinated Universal Time (UTC) minus 4 hours; Eastern zone is UTC minus 5 hours; Central zone is UTC minus 6 hours; Mountain zone is UTC minus 7 hours; Pacific zone is UTC minus 8 hours; Alaska zone is UTC minus 9 hours; Hawaii–Aleutian zone is UTC minus 10 hours; Samoa zone is UTC minus 11 hours; and Chamorro zone is UTC plus 10 hours. For more information, please visit: https://doi.org/10.21949/1519143. A data dictionary, or other source of attribute information, is accessible at https://doi.org/10.21949/1529083 This dataset represents the official written time zone boundaries from USDOT’s Office of General Counsel per 49 CFR Part 71. Oversight of Time Zones was assigned to DOT due to the importance of time coordination for transportation related activities. Acknowledgment of the Bureau of Transportation Statistics (BTS). onGoing Dominic Menegus Bureau of Transportation Statistics (BTS) Geographer 202-306-1587 1200 New Jersey Ave. SE Washington DC 20590 US dominic.menegus@dot.gov pointOfContact asNeeded NTAD National Transportation Atlas Database National Transportation Atlas Database vector polygon Uniform Time Standard Time Time Zones theme none USA National Territories place none This NTAD dataset is a work of the United States government as defined in 17 U.S.C. § 101 and as such are not protected by any U.S. copyrights. This work is available for unrestricted public use. otherRestrictions Access Constraints: unrestricted National Transportation Atlas Database 2026-06-28 publication Bureau of Transportation Statistics (BTS) publisher largerWorkCitation vector eng; USA boundaries Native Dataset Environment: Version 6.2 (Build 9200) ; Esri ArcGIS 10.8.1.14362 -179.231101251189 179.859665728096 -14.6018060155132 71.4397857072312 2019-10-04 0 Time Zones A data dictionary resource of attribute information is accessible at https://doi.org/10.21949/1529083 Bureau of Transportation Statistics (BTS) NTAD Program Manager 1200 New Jersey Ave. SE Washington DC 20590 United States ntad@dot.gov distributor None. No fees are applicable for obtaining the dataset. https://doi.org/10.21949/1522274 http Open Data Catalog Web page to view and download dataset. The file download formats available include: ESRI File Geodatabase or Shapefile, GeoPackage, Comma-Seperated Values (CSV), Microsoft Excel, GeoJSON, KML, Feature Collection, and SQLite Geodatabase. download https://doi.org/10.21949/1522276 http ArcGIS REST Services Directory Feature Server (WFS) complies with OGC WFS Map Service for visualizing geospatial information download https://doi.org/10.21949/1403512 http Repository and Open Science Access Portal (ROSA P) NTAD Archive Collection ZIP download dataset Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. The Time Zones dataset was created by consulting the Office of General Council (OGC)'s time zone boundary document. Made a list of geographic from the document that were then verified from authoritative sources i.e. Census, BLS, USACE, etc. All components were added in ArcGIS along with manually generated lines of longitude. Features were traced to create boundary line, then transforms into polygons. Discrepancies that were found were communicated back to OGC for potential future rule changes to the Code of Federal Regulations Standard Time Zone Boundaries. OSAV reviews then GIS experts peer review the data specific to their extertise. BTS conducts a final peer review and the data is published. asNeeded Dominic Menegus Bureau of Transportation Statistics (BTS) Geographer 202-306-1587 1200 New Jersey Ave. SE Washington DC 20590 United States dominic.menegus@dot.gov custodian